Abstract: Since the conformal structure has excellent aerodynamical performance and does not have the thermal gradient caused by the discontinuous surfaces, the missile radome with such structure may improve the velocity and effective range of the missile system. However, the curved surface of the aspherical radome used in the conformal structure allows the radome to have many dynamic characters different from the spherical structure, which makes it difficult to design the optical system in a target seeker. Based on analysis of the firstorder characteristics of conformal structure, the reason why the primary order aberration is generated and its characteristics are analyzed according to the vector aberration theory, and a method to tradeoff the aberration in all the observation FOVs is proposed. The result of simulation shows that the addition of the tilt and off-center elements can magnify the aberration in narrow FOV, and can improve the imaging quality of this conformal structure.